In the sales and marketing industries, the ability to send e-mail messages about offers for goods and services such as coupons can greatly enhance the chances that the recipient will read the e-mail messages, and also enhances the chances that the individual will purchase the goods and services being advertised in the e-mail messages. If the offers included in the e-mail messages are expired or invalid, the recipient may become frustrated, and may even ignore future e-mail messages from the same company.